[gdal-dev] issues with gdal2tiles.py

[Marcela Campo]

Hi André, thank you for your response.

I am not using EPSG:900913 anywhere

I got some img files someone else processed in arcgis and I am processing
them this way:

gdal_translate -of GTIFF -co "COMPRESS=LZW" -scale 0 255 0 255 -ot Byte
input.img  input.tif
gdalwarp  -t_srs "EPSG:3857" input.tif output_p.tif
gdal2tiles.py output_p.tif

I tried forcing the source projection during warp this way

gdalwarp -s_srs "EPSG:22184" -t_srs "EPSG:3857"  input.tif output_p.tif

I am not sure about source projection, I found it out doing:

gdalinfo -proj4 input.img

and searching for the proj4 string in the internet. The image is actually
from the zone of projection EPSG:22184 so I believe is ok.

In what point of the process you say I should be forcing with a_srs?

Thanks!
Marcela



On Tue, May 27, 2014 at 11:53 AM, Andre Joost <andre+joost at nurfuerspam.de>wrote:

> Am 27.05.2014 05:31, schrieb Marcela Campo:
>
>  Hi,
>>    I am trying to use gdal2tiles with a set of geotiff and I get the
>> following error
>>
>> ERROR 6: EPSG PCS/GCS code 900913 not found in EPSG support files.  Is
>> this
>> a valid
>> EPSG coordinate system?
>> ERROR 6: No translation for an empty SRS to PROJ.4 format is known.
>>
>>
>> I have already transformed to projection EPSG:3857, here is the gdalinfo
>> output for one of the files
>>
>
>  the command generates the tiles, but as the images appear a bit shifted I
>> wonder if it somewhat misinterpreted the projection.
>>
>>
> Instead of reprojecting to EPSG:900913 (which will place the points on the
> same spot on the globe), try to assign the projection with -a_srs. This
> will effectively shift the points.
>
> If the shift goes in the wrong direction, try EPSG:3395. This is the
> projection on a ellipsoid rather than a sphere.
>
> HTH,
> André Joost
>
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